They force foreign manufacturers to create local businesses with 50% chinese share.

A necessary strategy for any developing nation. If you allow imports with no local manufacturing requirement, other nations have incentives to dump products onto your markets to increase production. Open trade only really works if both sides can see eye to eye. Otherwise the developing nation will be stuck producing cheap products with little to no added value.

Hong Kong had unilateral free trade throughout decades of almost uninterrupted economic growth. If you produce cheap products you develop expertise that you can leverage to eventually produce more expensive ones. This process of learning by doing does not depend on tariff barriers and tariff barriers will not make it work either. Argentina produced cars domestically for decades that were more expensive and higher price than the world market and as soon as tariff protection was withdrawn the industry disappeared, after having wasted millions of dollars over decades.

this is a good way to avoid getting colonized by american companies

didn't know that.how would they measure chinese share. these days with trust funds i imagine it's pretty difficult to know exactly who owns something

That's just common sense for a developing economy.

until Tesla came :)